I see theater and movies as a way of fishing stories out of humanity and using them to provide vicarious learning experiences. As a historian, I gravitate towards clothing as experimental archaeology. If you can't wear it, there's a good chance they couldn't back then either.
My ultimate goal in costuming varies wildly depending on when you ask me. I love laboriously researching and creating period garments by hand and I'm fascinated by folk costume, but I'm constantly interested in using non-traditional materials on the human body and getting dirty to put someone in something amazing.
Someday, I will be a talking head on the History Channel, I will costume the next great Napoleonic War naval epic, and I will figure out how to make a tailored suit out of silver lame'.